return new Promise((resolve, reject) => {
     dir.files(process.cwd(), (err, files) => {
         if(err) {
             reject(err);
         } else {
             resolve(applyFilter(files, filter));
         }
     });
 });

    const hostRule = (ruleName, subdir, subdirS) => {
        dir.files(subdir, (err, files) => {
            if (err) {
                throw err;
            }

            let relativeDir = '/gamerules/';
            for (let i = 2; i < subdirS.length; i = i + 1) {
                relativeDir += subdirS[i] + '/';
            }

            files.forEach((file) => {
                const fileS = file.split(/[\/\\]/);
                const route = relativeDir + fileS[fileS.length - 1];
                console.log('Setting route ' + route + ' => ' + file);
                app.get(route, (req, res) => {
                    res.sendFile(file);
                });
            });

        });
    }

        next();
    },
    function(err, files){
        console.log('finished reading files:',files);
    });


// the callback for each file can optionally have a filename argument as its 3rd parameter
// and the finishedCallback argument is optional, e.g.
dir.readFiles("./", function(err: any, content: any, filename: string, next: any) {
    console.log('processing content of file', filename);
    next();
});

dir.files("./", function(err, files) {
    console.log(files);
});

dir.files("./", function(err, files) {
    // sort descending
    files.reverse();
    // include only certain filenames
    files = files.filter(function(file: any) {
       return ['allowed', 'file', 'names'].indexOf(file) > -1;
    });
    // exclude some filenames
    files = files.filter(function(file: any) {
        return ['exclude', 'these', 'files'].indexOf(file) === -1;
    });
});